Tub with removable strainer plug for vibratory finisher



Jan. 25, 1966 E5 .4 35 f 'I' .Illllllll J. F. RAMPE TUB WITH REMOVABLE STRAINER PLUG FOR VIBRATORY FINISHER Filed Sept. 10, 1962 4 '23 2'2 I 3 H l! 6 lia I W W 4 INVENTOR JOHN E PAM/ E BUM/M, 5W

United States Patent 3,231,093 TUB WITH REMOVABLE STRAINER PLUG FOR VIBRATORY FINISHER John F. Rampe, 3417 Fairfax Road, Cleveland Heights, Ohio Filed Sept. 10, 1962, Ser. No. 222,522 8 Claims. (Cl. 210-477) This invention relates to a vibratory finishing tub, particularly a tub with provision for optionally permitting or preventing gravity discharge of its liquid contents.

Vibratory finishing tubs are widely used for a variety of purposes; for example, for removing burrs from goods that have been machined or formed by casting from metal, plastic or composition stock. The usual practice is to deposit the goods in the tub together with a suitable abrading medium such as stones or chips and, after having done so, to introduce a liquid which in a typical case may be a coating composition, a degreasing medium, or water containing a detergent. The tub is then vibrated as long as necessary to complete the finishing operation. Ordinarily, following finishing, the liquid is drained off before the goods are removed. This is often done by decanting but is more easily accomplished by some kind of bottom drainage provision. The latter, if present, must be such as to resist the disruptive effects of vibration.

The present invention has as an object to provide a vibratory finishing tub with vibratioh-proof drainage means in its lowermost portion. With this in mind, use is made of an external closure, an internal strainer plug, and a plug seat formed in an encompassing body of a yieldable plastic material at the bottom of the tub. A related object is to provide a drainage plug which can be snapped into place in such body of plastic material and which, when once urged into position, is not likely to be dislodged by the vibrations to which the tub is subjected or displaced accidentally.

In the preferred embodiment of the invention, the strainer plug is made of a sturdy material with desirable wear-resistance properties. Because the plug is exposed to the possibility of wear and damage by the goods being finished, it is necessary that it be suificiently impactand abrasion-resistant so that it will not wear out within an unduly short time. To this end, it may to good advantage be formed as hereinafter described of a material that is harder than the encompassing body of yieidable plastic material. If desired, the latter may not merely surround the plug but advantageously can be continued across the bottom and up along the side walls of the tub to serve as a lining for it.

Other objects, advantages and features of the invention will be apparent from the description which follows and from the accompanying drawings, in which:

FIGURE 1' is a top plan of the vibratory finishing tub ofthe present invention.

FIGURE 2 is a corresponding end elevation.

FIGURE 3 is a fragmentary section on line 3-3 of FIGURE 2 and enlarged relative to that figure.

FIGURE 4 is an exploded view of the components seen in FIGURE 3 after rotation through an angle of 90.

FIGURE 5 is a top plan of the strainer plug.

In FIGURES l and 2, the scale is reduced; in FIG- URES 3 to 5, it approximates full size.

The vibratory finishing tub I of the present invention appears in FIGURES 1 and 2. Of the nature of a receptacle, it takes the form in the preferred embodiment of the invention of a hollow cylinder with sleeves 2 welded to its ends. These sleeves constitute parts of oppositely directed tub-supporting trunnions. To help in carrying the tub, installing it, and removing it from the machine inwhich it is employed, the tub is provided with side handles 3. These handles are mounted on upstanding flanges 4 that frame and thus parallel each other on opposite sides of an oblong access opening 5 at the top of the tub. Preferably, tub I, mounting sleeves 2, handles 3 and flange 4 are made of a suitable stiff impact-resistant shape-retaining material such as steel or other metal.

The tub I is lined throughout with a coating 6 (FIG- URE 2) of a yieldable plastic material, preferably one that is solvent resistant, derived from a commercial plastisol. Typically, such a plastisol consists of a suspension in a volatile organic medium of an incompletely polymerized synthetic resin of the vinyl family; e.g., vinyl chloride, vinyl acetate, or a vinyl chloridevinyl acetate copolymer. On curing at temperatures up to about 350 F., the incompletely polymerized components of the plastisol convert to a more highly polyurerized form. After the volatiles have been eliminated, the resin takes on the characteristics of a typical rubbery or elastomeric material with a durometcr hardness of the order of from about to about 70. This is not enough to prevent a limited amount of yielding upon the application of a moderate force such as is achieved by pressing with ones finger.

Near the bottom center of the tub, the coating 6 merges into an integral bottom mass 7 of the-same material with a maximum thickness, in a representative case, of the order of l". The coating 6 and the bottom mass 7 can be formed, applied or built up in any one of several ways such as by introducing an excess of the plastic material, preferably in the form of a plastisol susceptible of being cured in situ While it is in liquid or semi-liquid form, into the previously cleaned and heated (to about 350 F.) steel tub, pouring out or otherwise removing the excess, and completing the cure as by heating at about 350 F. for 30 minutes or other suitable period. Desirably, an adhesion agent is applied to the tub interior after cleaning and before the resin is placed therein.

Seated and centered in the bottom mass 7 is a strainer plug 8 surrounded by an approach surface 9 of frustoconical shape; the latter is itself surrounded by a substantially fiat surface 10 (FIGURE 2). The frustoconical approach surface 9 constitutes the entrance portion of a passageway extending through the bottom mass '7, tub wall 11, and, if the closure is open, through those elements at the bottom of the tub which make up the closure assembly. Located at the bottom of the tub, this passageway serves as a gravity discharge opening. Under proper conditions, the liquid contents of the tub can be drained through it, leaving only the finished goods and solid materials in the tub.

The elements previously referred to as making up the closure assembly include two depending stout metal clips 12 welded to the outside of the tub wall 11 in spaced parallel relation as shown in FIGURE 3. The clip members 12 are L-shaped, each consisting of a long leg portion 12a and a short inwardly extending leg portion 121'), the leg portions of each clip member being at a right angle to each other. These clips normally support an oblong metal plate 13 provided with a tapped opening at its geometrical center, such. plate being somewhat shorter than the distance between the two clips. To act as a stop for the plate 13, a longer locating bar 14 of metal is welded to it along one of its two longer sides. Together, the plate 13 and the locating bar 14 form a cross head which, along with the components associated with it, may be released and removed by urging it to one side of and away from the clips 12.

A captive metal screw 15 carrying a handle 16 at its projecting bottom end is threaded into the tapped opening in the plate'13. At the end opposite the handle 16,

the screw has a fr-usto-conical head 17 that fits loosely in a correspondingly shaped recess in metal washer 1S appearing to advantage in FIGURE 3. The washer is welded as at 19 to the outer face of a circular metal backing plate 20, the latter being of less diameter than the distance between the leg portions 12a of the clips in order that the backing plate can be received easily between the clips. On the upper face of this backing plate 20 is a thick pad 21 of a solvent-resistant resilient sealing material; it is desirable that the pad 21 be resilient in order to conform to the cylindrical contour of the tub. The tub bottom is provided as shown in FIGURE 3 with a circular opening 22 which constitutes part of the previously mentioned passageway through which, when the closure is open, the liquid contents of the tub may escape.

Immediately above the opening 22 in the tub wall 11 is an air space 23 resulting from the presence in the bottom mass 7 of an internal annular shoulder 24. As will be apparent from FIGURE 4, the upper face 25 of the shoulder 24 comprises a fiat seating surface of annular shape on which the plug 8 comes to rest. Immediately above it is frusto-conical surface 26 that flares outwardly in the discharge direction to form an undercut portion 27; see FIGURE 4.

AbOVe the undercut portion 27, likewise in the bottom mass 7, is a shallow cylindrical portion 28 of the same diameter as the minimum diameter of the frustomonical approaoh surface 9. The net result of separating the two oppositely directed frust-o-conical surfaces by the cylindrical portion 28 is to form a short throat the upper and lower limits of which are seen as lines 29 and 30 in FIG- URE 4. It will be noted that the effective width of the opening 22 in the tub wall 11 is less than the internal diameter of the shoulder 24, which in turn is less than that of the throat. It will also be noted that the angle of taper of the frusto-conical surface 26 is somewhat less than that of the frusto-conical surface 9.

The plug 8 comprises a shallow body 31 of synthetic resin provided with a multiplicity of suitably distributed openings 32 which flare in the discharge direction. The top 33 and bottom 34 faces of the plug are fiat; the former constitutes the upper limit of a cylindrical portion 35 which corresponds in size and shape to the throat 28. Between the cylindrical portion 35 and the bottom face 34 is a frusto-conical flared portion 36. The minimum diameter of this frusto-conical portion 36 is the same as that of the cylindrical portion 35; the maximum diameter is that of the fiat bottom face 34. The plug 8 thus can be described as a modified conical frustum conforming in shape to the surfaces 25, 26 and 28.

Preferably, the plug 8 is formed of a suitable relatively hard synthetic resin such as a polyurethane having a durometer value of from about 20 to about 30 units greater than that of the synthetic resin used in the bottom mass 7; e.g., in the example given wherein the bottom mass comprises a polyvinyl chloride resin having a durometer value of from 60 to 70, the plug 8 has a durometer value of the order of about 90.

When the plug 8 and the bottom mass 7 are assembled, the bottom mass 7 will tend to yield under forces exerted on the plug, which retains its shape. To effect assembly, pressure on the plug forces the bottom mass to yield sufficiently to permit the plug to enter into the throat 28. Continued pressure on the plug results in entry of the frusto-conical portion of the plug into the undercut area 27. In the assembly process, the plug 8 snaps into position with the bottom surface 34 seating on the annular surface 25 and the frusto-conical portion 36 in contact with the frusto-conical Wall 26 below the throat 23.

With the plug 8 in place, displacement of the plug in a downward direction is impossible in consequence of the fact that it is supported directly by the shoulder 24 on the bottom mass 7 and indirectly by the portion of the tub wall 11 surrounding opening 22. Upward displacement, particularly accidental displacement, is impeded by the throat 28. The drain openings 32 will permit the liquid contents of the tub to escape if the sealing pad 21 is not in contact with the tub wall 11. With the pad 21 secured in place as shown in FIGURE 3, the tub is virtually liquid-tight so far as its bottom construction is concerned.

The hardness differential between the bottom mass 7 and the plug 8 is doubly advantageous, first in that it makes possible the above-described snap-in action and second in that the plug is better able to resist the impact of goods introduced into the tub for finishing. A plug of soft material would not stand up so well under the impact of a heavy object. Neither would it stand up well under the pressures exerted on it by a full load. On the other hand, the bottom mass 7 and the coating s of which it is a continuation need not be especially hard; rather, they should be soft enough to prevent damage to the tub by the goods being vibrated in the tub.

It is evident that changes may be made without departing from the spirit of the invention. Thus the closure assembly may take sundry other forms than that shown, including forms in which the closure itself is hinged to the tub bottom. The plug may be of various other materials than polyurethane; if of another synthetic resin,

the latter may be a glass-reinforced resin. The yieldable plastic material used in the bottom mass 7, including the tub lining extending upward therefrom, needs not necessarily be of synthetic resin but may, if desired, be of a. material such as rubber that is of natural origin. Other changes can be expected to suggest themselves to those skilled in the art.

It is intended that the patent shall cover, by summarization in appended claims, all features of patentable novelty residing in the invention.

What is claimed is:

1. A vibratory finishing tub taking the form of a receptacle having a wall lined with an elastomeric material with provision for optionally permitting or preventing the discharge of liquid from the receptacle, such provision comprising an opening in the receptacle wall; a massive body of elastomeric material with a similar opening therein inwardly of the opening in the receptacle, said body of elastorneric material being integral with that of the lining; a generally annular seat in the body of elastomeric material, said seat having associated therewith a frusto-conical surface that widens in the discharge di rectron; a perforated abrasion-resistant synthetic resin strainer plug removably positioned on such generally annular seat, said plug having thereon a complementary frusto-conical surface; and a closure outwardly of the portion of the receptacle wall in which the opening occurs, the geometry of the strainer plug, its seat and the opening in the receptacle wall being such as to minimize tlie possibility of accidental displacement of the strainer p ug.

2. A vibratory finishing tub according to claim 1 wherein the effective width of the opening in the receptacle wall is less than the maximum width of said strainer plug.

3. A vibratory finishing tub according to claim 1 wherein said strainer plug is of an impact-resistant synthetic resin.

4. A vibratory finishing tube according to claim 1 wherein said massive body of elastomeric material has a durometer hardness of the order of 70.

5. A vibratory finishing tub according to claim 4 wherein said strainer plug has a durometer hardness from 10 to 20 units greater than that of said massive body of elastomeric material.

6. In a vibratory finishing tub having one wall provided with a through opening, a lining of relatively soft yieldable rubbery material adhering to the inside of the tub wall about the opening, said lining being several times as thick as the wall and formed with an opening registered with the wall opening, said lining opening comprising a series of contiguous circular portions of different diameters, one of the circular portions being adjacent the wall opening and of less diameter than the next adjacent circular portion as a result of the provision of a circular radial shoulder at the juncture of said one and said next circular portions, said shoulder being spaced axially of the lining opening from the inside surface of the tub wall, a perforated circular strainer plu-g removably disposed in the opening in the lining and seated against said shoulder, the wall of said next circular portion of the opening in the lining being undercut and the periphery of the plug being formed complementally thereto to provide a mechanical interlock, and the lining material being adapted to yield for distension of its opening in assembly therein of the plug and to return by inherent resiliency into yielding embracing relation to the plug thereby establishing the interlock.

7. A tub as defined in claim 6 wherein the lining opening includes a cylindrically walled portion spaced axially and inwardly of the tub from the shoulder and the strainer plug has a cylindrically walled peripheral portion engaged by said cylindrical wall of the opening.

References Cited by the Examiner UNITED STATES PATENTS 298,172 5/1884 Cave 210498 1,907,120 5/1938 Rishel 2171 10 2,355,979 8/ 1944 Keyser 4295 2,386,293 10/ 1945 Clements 220-57 2,457,927 1/ 1949 Scudder 220-57 2,964,187 12/ 1960 Riedel 209399 REUBEN FRIEDMAN, Primary Examiner.

HERBERT L. MARTIN, Examiner.

F. W. MEDLEY, Assistant Examiner. 

1. A VIBRATORY FINISHING TUB TAKING THE FORM OF A RECEPTACLE HAVING A WALL LINED WITH AN ELASTOMERIC MATERIAL WITH PROVISION FOR OPTIONALLY PERMITTING OR PREVENTING THE DISCHARGE OF LIQUID FROM THE RECPTACLE, SUCH PROVISION COMPRISING AN OPENING IN THE RECEPTCLE WALL; A MASSIVE BODY OF ELASTOMERIC MATERIAL WITH A SIMILAR OPENING THEREIN INWARDLY OF THE OPENING IN THE RECEPTACLE, SAID BODY OF ELASTOMERIC MATERIAL BEING INTEGRAL WITH THAT OF THE LINING; A GENERALLY ANNULAR SEAT IN THE BODY OF ELASTOMERIC MATERIAL, SAID SEAT HAVING ASSOCIATED THEREWITH A FRUSTO-CONICAL SURFACE THAT WIDENS IN THE DISCHARGE DIRECTION; A PERFORATED ABRASION-RESISTANT SYNTHETIC RESIN STRAINER PLUG REMOVABLY POSITIONED ON SUCH GENERALLY ANNULAR SEAT, SAID PLUG HAVING THEREON A COMPLEMENTARY FRUSTRO-CONICAL SURFACE; AND A CLOSURE OUTWARDLY OF THE PORTION OF THE RECEPTACLE WALL IN WHICH THE OPENING OCCURS, THE GEOMETRY OF THE STRAINER PLUG, ITS SEAT AND THE OPENING IN THE RECEPTACLE WALL BEING SUCH AS TO MINIMIZE THE POSSIBLILTY OF ACCIDENTAL DISPLACEMENT OF THE STRAINER PLUG. 